The present invention relates to the field of antimicrobial agents.
The use of antibiotics by humans can be seen as an evolutionary experiment of enormous magnitude, a window from which to view not-quite-natural selection operating in real time. Within 50 years, the number of species and strains of pathogenic and commensal bacteria resistant to antibiotics and the number of antibiotics to which they are resistant has increased virtually monotonically world-wide. As a result, infections that had been readily treatable by chemotherapy may no longer be so. It is clear that the evolution and spread of resistance can be attributed to the use and overuse of antibiotics. Increased resistance of bacterial infections to antibiotic treatment has been extensively documented and has now become a generally recognized medical problem, particularly with nosocomial infections. See, for example, Jones et al., Diagn. Microbiol. Infect. Dis. 31:379–388, 1998; Murray, Adv. Intern. Med. 42:339–367, 1997; and Nakae, Microbiologia 13:273–284, 1997.
Throughout the developed world there is public and governmental concern about the increasing prevalence of antimicrobial resistance to chemotherapy in bacteria that cause diseases in humans. Many pathogens exist for which there are few effective treatments, and the number of strains resistant to available drugs is continually increasing. New antimicrobial agents and improved methods are thus needed for the treatment and prevention of infections by such pathogens.